Long-distance free-space distribution of quantum entanglement

Science. 2003 Aug 1;301(5633):621-3. doi: 10.1126/science.1085593. Epub 2003 Jun 19.

Abstract

We demonstrate the distribution of quantum entanglement via optical free-space links to independent receivers separated by 600 m, with no line of sight between each other. A Bell inequality between those receivers is violated by more than four standard deviations, confirming the quality of the entanglement. This outdoor experiment represents a step toward satellite-based distributed quantum entanglement.